Interface and method of forming an interface for a silicon contact

ABSTRACT

In a semiconductor device using a polysilicon contact, such as a poly plug between a transistor and a capacitor in a container cell, an interface is provided where the poly plug would otherwise contact the bottom plate of the capacitor. The interface bars silicon from the plug from diffusing into the capacitor&#39;s dielectric. The interface can also include an oxygen barrier to prevent the poly plug from oxidizing during processing. Below the interface is a silicide layer to help enhance electrical contact with the poly plug. In a preferred method, the interface is created by selectively depositing a layer of titanium over a recessed poly plug to the exclusion of the surrounding oxide. The deposition process allows for silicidation of the titanium. The top half of the titanium silicide is then nitridized. A conformal ruthenium or ruthenium oxide layer is subsequently deposited, covering the titanium nitride and lining the sides and bottom of the container cell.

TECHNICAL FIELD

[0001] The present invention relates generally to a method of forming an interface for a silicon contact. More specifically, the invention relates to a barrier between two electrically conductive portions of a semiconductor device. In a particularly preferred implementation, the present invention relates to a diffusion barrier between a polysilicon plug and a capacitor plate that forms a part of a dynamic random access memory (DRAM).

BACKGROUND OF THE INVENTION

[0002] In the process of fabricating a memory cell for a DRAM or other memory device, it is often desirable to construct the capacitor portion of that memory cell so that the capacitor is elevated from the semiconductor substrate that supports the device. For example, it is known in the art to construct the access transistor portion of a memory cell relatively close to the surface of the substrate. The gate of the access transistor is above the substrate, separated only by a thin layer of oxide. Moreover, the source and drain of the access transistor are often doped portions of the substrate itself. It is further known to then provide an insulating layer, such as an oxide, over this access transistor and other devices, wherein the layer is thick enough to have a planar surface despite the features protruding from the substrate. A contact hole is etched through this oxide to one of the doped portions of the substrate and is filled with a conductive material, such as doped polycrystalline silicon, or polysilicon. The polysilicon filling this contact hole is often known as a poly plug. An additional layer of oxide is then formed over the first, and a container is etched from the additional oxide layer, wherein the bottom of the container corresponds with the top of the polysilicon plug. The capacitor is formed within this container. As part of this process, a layer of conductive material will be provided at least along the bottom of the container to serve as the capacitor's bottom plate. This step is followed by providing a dielectric layer over the bottom plate and a top plate over the dielectric layer. The contact between the bottom plate of the capacitor and the poly plug allows electrical communication between the bottom plate and between one of the transistor's doped substrate portions.

[0003] This known process raises several concerns. First, there is a tendency for the silicon in the poly plug to diffuse into the cell dielectric during fabrication, which decreases the performance of the capacitor. Second, there is a tendency for the poly plug to oxidize during the various processes performed after the poly plug is created. This oxidization inhibits the ability of the poly plug to channel electrical signals. These concerns are in addition to the fact that those skilled in the art are constantly striving to improve the electrical contact between the poly plug and the bottom plate of the capacitor. Moreover, such problems arise in other processes concerning silicon contacts, such as damascene processes.

SUMMARY OF THE INVENTION

[0004] Accordingly, the present invention provides a method of creating a silicon contact interface. In one exemplary embodiment, a diffusion barrier is provided during the fabrication of a memory cell and, more specifically, after forming the poly plug and before fabricating the capacitor portion of the memory cell. In a more specific embodiment, this barrier is created by siliciding and nitridizing a metal layer provided over the poly plug. In yet another exemplary embodiment, this diffusion barrier also serves as an oxidation barrier which protects the poly plug from oxidation. In still another exemplary embodiment, a second material is provided to act as the oxidation barrier. Other embodiments provide a diffusion barrier during the fabrication of other memory device elements, such as during a damascene process. Finally, the current invention also includes within its scope the products resulting from these processes.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005]FIGS. 1A through 1C depict an in-process semiconductor device as is known in the art.

[0006]FIG. 2 illustrates a known configuration for a container cell capacitor.

[0007]FIGS. 3, 4A through 4D, 5A through 5C, 6, and 7A through 7B represent steps that are taken in various exemplary method embodiments of the current invention.

[0008]FIG. 8 is a process flow diagram organizing the steps depicted in FIGS. 3, 4A through 4C, 5A through 5C, 6, and 7A through 7B.

[0009]FIGS. 9A through 9E show one preferred exemplary embodiment of the current invention.

[0010]FIGS. 10A through 10D illustrate a damascene process as known in the art. FIGS. 10E and 10F demonstrate the known way to complete an interconnect structure that began with the damascene process in FIGS. 10A-10D. FIG. 10G represents another exemplary embodiment of the current invention.

[0011]FIG. 11 is yet another exemplary embodiment of the current invention.

[0012]FIGS. 12A and 12B are still other exemplary embodiments of the current invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013]FIG. 1A depicts a portion of an in-process semiconductor device that, to this point, has been created by steps known in the art. An insulation layer 20 defines an opening 22, the bottom of which is generally level with the top of a portion of conductive material 24 that continues deeper into the insulation layer 20. The portion in FIG. 1A could be understood to represent one of several device portions at various stages of fabrication. For purposes of explanation, it will be assumed throughout most of the following discussion that FIG. 1A represents a portion of a memory cell, wherein opening 22 is actually a container 26, seen in FIG. 1B, designating the site where a capacitor will be formed. It follows then that the conductive material 24 in FIG. 1A can be more specifically identified as a poly plug 28 in FIG. 1B. Further, the insulating layer 20 is assumed to be an oxide 30, most likely silicon dioxide. Moreover, it is not necessary that one continuous insulation layer envelop the sides of both the container 26 and the poly plug 28. As seen in FIG. 1C, a second insulation layer 32 surrounds the sides of the poly plug 28 and defines the bottom of the container 26, while the oxide 30 defines the sides of the container 26. This is, in fact, the layering scheme that will occur if the process follows as described above in the background section. In addition, it is not necessary to use an oxide for the second insulation layer 32. In fact, it is preferable in the current invention if the second insulation layer 32 comprises a nitride at least around the poly plug 28, as this will help protect the poly plug 28 from oxidation during subsequent process steps. It should further be noted that, in illustrating a container cell/plug portion of a semiconductor device, it is understood that the poly plug 28 fills a hole extending down through the second insulation layer 32 and contacting the surface of the substrate 50, as seen in FIG. 1C. In the current application, the term “substrate” or “semiconductor substrate” will be understood to mean any construction comprising semiconductor material, including but not limited to bulk semiconductive materials such as a semiconductor wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). Further, the term “substrate” also refers to any supporting structure including, but not limited to, the semiconductive substrates described above.

[0014] At this point in the process, other devices, such as transistors, may flank the poly plug 28. Such elements and their placement in relation to the poly plug 28 and container 26 are well known in the art. Accordingly, they are omitted from the figures to more clearly illustrate the current invention.

[0015] Although FIGS. 1A through 1C can represent a container cell/plug portion of a semiconductor device, these figures can also represent an in-process damascene structure, which can be used to form interconnects between a word or bit line and a memory cell. The use of the current invention under these circumstances will be addressed further below. It follows that FIGS. 1A-1C could represent other stages in other areas of a semiconductor device as well.

[0016] Returning to the container cell/plug example, prior art teaches further processing as depicted in FIG. 2. A conductive material is layered along the sides and bottom of the container 26 to serve as a bottom plate 34, which in this case will be the storage node. A dielectric 36 is formed over the bottom plate 34, and another conductive material is layered over the dielectric 36 to form the top plate 38 which, in this embodiment, is the cell plate of the capacitor 40. Planarization and patterning of these layers 34, 36, and 38 are carried out as needed.

[0017] Because each step within the scope of the current invention may have several variations, FIG. 8 provides a flow chart which encompasses the embodiments that are graphically depicted in other figures included within this application. Accordingly, FIG. 8 serves to supplement the discussion below. FIG. 3 illustrates the first step in a preferred embodiment of the current invention, wherein a poly plug 28 is formed having a surface at a level below the bottom of the container 26. Preferably the surface of the poly plug 28 is about half-way between the bottom of the container 26 and the substrate 50. This can be achieved by forming polysilicon up to the bottom of the container 26 and subsequently recessing the poly plug 28 to a lower height through etching or other methods known in the art. Alternatively, the deposition process used to form the poly plug 28 could be halted before reaching the bottom of the container 26. While this step of forming a low or recessed surface for the poly plug 28 is not required by the current invention, it is preferred because it helps protect the sides and corners of the poly plug 28 from oxidation during further processing.

[0018] The next step comprises providing an initial barrier component 42 over the poly plug 28. This material is designated as an initial barrier component because, while initially it may not act as a diffusion barrier, the material at least contains components that can be used to create a barrier to the diffusion of silicon. In a preferred embodiment shown in FIG. 4A, the initial barrier component 42 is the result of selectively depositing titanium through chemical vapor deposition (CVD) onto the poly plug 28. The CVD process can be carried out under the following exemplary parameters: TiCl₄ for a source gas; H₂ for a reactive gas, wherein the flow rate of H₂ may be 2-10 times that of TiCl₄; Ar or He for carrier gasses; a substrate temperature of around 400 degrees C.; a reaction chamber pressure ranging from 0.2 to 2 torr; with an rf voltage applied to the reaction chamber. See, e.g., U.S. Pat. No. 5,173,327 by Sandhu et al. As a result of the selective CVD process, a layer of titanium will deposit only on the poly plug 28. The temperatures reached during the process, however, are sufficient to cause the titanium to react with the silicon in the poly plug 28 to form titanium silicide (TiSi_(x), where x is a positive number). It is possible to deposit relatively unreacted titanium onto the poly plug 28 at low enough temperatures, and the current invention certainly includes such a process and apparatus within its scope. However, it is actually preferable under the current invention to have a silicide layer above the poly plug 28, as such a layer will enhance electrical contact between the poly plug 28 and any overlying conductive material. Thus, if providing an initial barrier component 42 does not inherently result in an electrical contact enhancement material, then it is preferred that an additional step be taken to create such a material. Such a step is described further below, but for now, it is assumed that the selectively deposited initial barrier component 42 underwent silicidation during deposition, thereby forming an electrical contact enhancement layer 48 above the poly plug 28, as seen in FIG. 4B. Specifically, the CVD'd titanium underwent silicidation during CVD to form TiSi_(x).

[0019] Preferably only a monolayer of titanium silicide about five angstroms thick is formed, although it is not unusual to have a layer ranging from about five to 200 angstroms. For purposes of further explaining the current invention, it is assumed that the electrical contact enhancement layer 48 is a 100 angstrom-thick layer of titanium silicide.

[0020] It should be understood, however, that the initial barrier component 42 could comprise a different material as long as that material, either as initially deposited or with further processing, will help protect against the diffusion of silicon. Such materials include tungsten; rhenium; platinum group metals including platinum, palladium, iridium, ruthenium, rhodium, and osmium; oxides of those Pt-group metals, such as ruthenium oxide (RuO_(x), where x is a non-negative number, preferably 2); alloys of those Pt-group metals; and transition metal borides including TiB. Titanium is a preferred material because it is relatively easy to selectively deposit. Nevertheless, using ruthenium oxide for the initial barrier component 42 is an alternative preferred embodiment. As discussed below, it is sometimes desirable to provide a layer above the poly plug 28 to protect it from oxidation. For such a layer, selective deposition is not necessary. In some embodiments, this requires a layer in addition to the diffusion barrier. Ruthenium oxide, however, may have the benefit of acting as both a barrier against silicon diffusing from the poly plug 28 as well as a barrier against oxygen that might otherwise reach the poly plug 28. Accordingly, if ruthenium oxide is the material of choice for the initial barrier component 42, as shown in FIG. 4D, then that material may serve as both the diffusion barrier 44 and the oxidation protection layer 46. One skilled in the art may then proceed to forming the capacitor 40, comprising layers 34, 36, and 38, in the manner described above. The ruthenium oxide will serve as an interface—a common boundary—between the two conductive elements which, in this case, are the poly plug 28 and the bottom plate 34. Again, planarization of the layers, including the diffusion barrier 44/oxidation protection layer 46, as well as patterning steps, are carried out as needed. Similarly, if iridium is chosen for the initial barrier component 42, it, too, may act as both the diffusion barrier 44 and the oxidation protection layer 46 shown in FIG. 4D. Moreover, any material from the platinum metal group (including platinum, rhodium, palladium, and osmium) and their corresponding metal oxides may also serve dual roles as a diffusion barrier 44 and an oxidation protection layer 46.

[0021] Thus selectivity, while preferred in certain embodiments, is not a necessary requirement under the current invention. It may be more desirable in some embodiments to deposit a conformal initial barrier component 42 and then pattern the initial barrier component so that it remains only over the poly plug 28, as illustrated in FIG. 4A. Alternatively, it is possible to allow the conformally deposited initial barrier component 42 to remain as a lining along the container 26, as shown in FIG. 4C, with a planarization step taken if it is necessary to restrict the initial barrier component 42 to within the container 26. If tungsten is used as the initial barrier component 42, for example, CVD parameters would include using WF₆ and H₂ as precursors at 450 degrees C. and at a pressure of 80 torr. See, e.g., U.S. Pat. No. 5,654,222 by Sandhu et al.

[0022] Returning to the preferred embodiment in which titanium silicide is used as the electrical contact enhancement layer 48, the process moves from the step depicted in FIG. 4A to a nitridation step, the result of which is illustrated in FIG. 5A. It is preferred that the nitridation be carried out using an N₂/H₂ plasma. Parameters for this process include a temperature of around 600 to 675 degrees Celsius, a pressure of about 1 torr, a power of about 500 watts, and a flow rate generally ranging from 10 to 1000 sccm for the N₂ and H₂ gasses. This process continues until a titanium nitride (TiN) layer about 50 angstroms thick is created from the initial barrier component 42. This results in having nitridized about one-half of the electrical contact enhancement layer 48. As seen in FIG. 5A, the TiN layer serves as one embodiment of the diffusion barrier 44 sought under the current invention. While alternate embodiments of the current invention may call for fully nitridizing the initial barrier component 42, as seen in FIG. 5C, it is preferred to retain a portion of un-nitridized titanium silicide for improved electrical communication. In embodiments where the initial barrier component 42 has yet to become an electrical contact enhancement layer 48, it is still preferable to retain an un-nitridized portion of that layer, as it can later become an electrical contact enhancement layer 48 in a step described below. Regardless of the particular depth of the nitride, that material acts as a barrier to silicon, which has a tendency to diffuse from the poly plug 28 into the capacitor that is to be constructed in the container. Using a plasma process for nitridation is preferred because it can be done in situ—in relatively the same environment where the initial barrier component 42 was deposited. This reduces the risk of exposing the in-process device to contaminants.

[0023] Nevertheless, other nitridation methods fall within the scope of the current invention. Such methods include a thermal process such as an N₂/NH₃ anneal. This method would most likely be used if tungsten served as the material for the initial barrier component. In this case, the tungsten could be exposed to an N₂/NH₃ ambient under a pressure of approximately 4.5 torr and having a temperature of about 360 degrees C. Further, approximately 350 W of RF power could be applied to generate plasma from the gasses, which can occur in an N₂:NH₃ ratio ranging from 2:1 to 50:1. As for duration, this anneal process continues until the desired amount of tungsten nitride has been formed from the initial barrier layer. Thus, if the initial barrier component 42 is made of tungsten and covers only the poly plug 28, as in FIG. 4A, the nitridation step creates a tungsten nitride diffusion barrier 44, as represented in FIG. 5A. If, on the other hand, the initial barrier component 42 was a conformal layer of tungsten, represented by FIG. 4C, then the nitridation step would result in a conformal layer of tungsten nitride serving as the diffusion barrier 44. This is demonstrated in FIG. 5B, wherein the initial barrier component 42 has been partially nitridized. Further, if the initial barrier component 42 is made of ruthenium or any other Pt-group metal, the nitridation processes described above as well as others known in the art can be used to form a nitride diffusion barrier 44.

[0024] As a result, an interface is created by the above described process, wherein both the process and the resulting structure fall within the scope of the current invention. Accordingly, one skilled in the art could return to known steps and construct a capacitor within the container 26 and over the diffusion barrier 44.

[0025] However, it is preferred in other embodiments to further develop the interface. If silicidation has not occurred by this point in the process, such a step may be performed now. As discussed above, this enhances the electrical contact between the poly plug 28 and the capacitor that will be constructed thereover. Assuming that (1) generally unreacted titanium has been selectively deposited as the initial barrier component 42, and (2) only the top 50 angstroms of the titanium has been nitridized, then at this step in this particular embodiment, the remaining 50 angstroms of titanium are changed into titanium silicide. Silicidation can be conducted using any known method but is preferably performed using a rapid thermal anneal process at about 650 degrees C. for as long as necessary to achieve the desired amount of TiSi_(x). The result of this process is depicted in FIG. 6: a TiSi_(x) layer that acts as an electrical contact enhancement layer 48 is formed under the diffusion barrier 44. The formation of this electrical contact enhancement layer 48 helps to counteract the effects of any oxide within the poly plug 28 that has developed up to this point. Much of this oxidation occurs at the top of the poly plug 28. Thus, although a 50 angstrom measurement is used as an example thickness of the electrical contact enhancement layer 48, it is preferred that enough silicon in the poly plug 28 be reacted during silicidation so that a relatively oxide free portion of the poly plug 28 remains. This silicidation process may also be used in other embodiments, including those using unreacted tungsten as the initial barrier component 42, wherein silicidation will result in an electrical contact enhancement layer 48 made of tungsten silicide (WSi_(x)). Alternatively, silicidation of a ruthenium initial barrier component 42 will result in an electrical contact enhancement layer 48 made of ruthenium silicide. Similarly, if the initial barrier component 42 is rhenium or any Pt-group metal, silicidation will result in an electrical contact enhancement layer 48 comprising a silicide of the original material.

[0026] Still another step that could be performed includes providing an oxidation protection layer 46, which helps protect the poly plug 28 from oxidation during further processing. In several embodiments, this step involves the CVD of a metal, such as rhenium or the Pt-group metals. Alternatively, an oxide of these metals could be used for this layer 46. As another option, an alloy comprising a selection of the metals listed above could be used. As an example of this step, the CVD of ruthenium can be accomplished with a substrate temperature ranging from about 225 to 325 degrees Celsius (more preferably 250 degrees C.) and a pressure of around 3 torr (more preferably 1 torr). Precursor chemistries include organoruthenium complexes, such as bis(cyclopentadienyl) ruthenium (Ru(C₅H₅)₂), triruthenium dodecacarbonyl (Ru₃(CO)₁₂), tricarbonyl (1,3-cyclohexadiene) ruthenium, and the like. Alternatively, a halogenated compound, such as ruthenium tetrachloride (RuCl₄), RuCl₃, or RuF₅ could be used. The CVD of ruthenium oxide involves a similar reaction but requires a lower temperature—around 150 degrees C.—due to the addition of oxygen to the reaction.

[0027] Regardless of the particular metal, metal oxide, or alloy deposited, the result appears in FIG. 7A, wherein a conformal oxidation protection layer 46 ranging from 1 to 300 angstroms in thickness lines the container 26 and overlies the diffusion barrier 44. The diffusion barrier 44, in turn, overlies the electrical contact enhancement layer 48, with the poly plug 28 under all of the above elements. FIG. 7B depicts the result in an embodiment wherein the diffusion barrier 44 is conformal to the container 26, and the oxidation protection layer 46 is conformal to the diffusion barrier 44. Once one skilled in the art provides the oxidation protection layer 46, he or she may continue with steps known in the art. In this case, that will entail building a capacitor, beginning with providing a conductive layer within the container 26 to serve as the capacitor's bottom plate.

[0028] For purposes of clarity, FIGS. 9A through 9F reiterate a preferred embodiment of the current invention. A low surface for the poly plug 28 is provided as depicted in FIG. 9A. In FIG. 9B, an initial barrier component 42 including titanium is selectively deposited through CVD. The deposition conditions cause the titanium to react with the silicon in the poly plug 28 to form titanium silicide, thereby allowing the initial barrier component 42 to act as an electrical contact enhancement layer 48. FIG. 9C demonstrates that the top portion of the electrical contact enhancement layer 48 is subsequently nitridized to form the diffusion barrier 44. Next, an oxidation protection layer 46 made of ruthenium or ruthenium oxide is conformally layered within the container 26 and over the diffusion barrier 44, as seen in FIG. 9D. With the completion of the interface—comprising layers 44, 46, and 48—prior art steps may then be resumed, such as those depicted in FIG. 9E, involving layering the bottom plate 34, dielectric 36, and top plate 38 of a capacitor 40 over the oxidation protection layer 46. Planarization may also be performed as appropriate.

[0029] As mentioned above, the current invention can also play a part in a damascene process, which may be used to form an electrical connection between two portions of a semiconductor circuit. For example, a damascene structure can serve as an interconnect between a bit line or word line and a device such as a transistor. Damascene essentially involves forming a hole within an insulation layer and filling that hole with metal, as opposed to etching away undesired portions of a continuous metal layer and surrounding the remaining portions with insulation. The process for forming a damascene structure as known in the prior art is depicted in FIGS. 10A through 10D. FIG. 10A shows a first insulative layer 52 formed over the substrate 50. In FIG. 10B, a photoresist pattern 54 is formed over the first insulative layer 52. Etchants, indicated by the arrows 56, remove a portion of the first insulative layer 52 that is not protected by the photoresist pattern 54, as seen in FIG. 10C. This portion is filled with a conductive material 24 which, in this case, is assumed to be doped polysilicon. FIG. 10D illustrates that any conductive material above the surface of the insulative layer 52 is removed through processes such as planarization. Once the damascene structure is completed, further processing completes the interconnect structure. For example, FIG. 10E indicates that a second insulative layer 58 is subsequently formed over the first insulative layer 52 and is patterned and etched to expose an opening 22 above the conductive material 22. FIG. 10F illustrates that this opening 22 is then filled with a conductive wiring material 60, which may serve as a bit line or word line.

[0030]FIG. 10G illustrates an embodiment of the current invention in the context of a damascene process. After the first insulative layer 52 has been etched, the portion that has been etched away is replaced with the polysilicon conductive material 24. Preferably, the surface of the conductive material 24 is lower that the surface of the first insulative layer 52. More preferably, the surface of the conductive material 24 is about half-way between the surface of the first insulative layer 52 and the substrate 50. Next, an initial barrier component 42 including titanium is selectively deposited upon the conductive material 24 and silicided in that deposition process. The initial barrier component 42 is subsequently nitridized to form a diffusion barrier 44, while the remaining silicided portion forms an electrical contact enhancement layer 48. Once the oxidation protection layer 46 is formed using a Pt-group metal or an oxide of a Pt-group metal, the conductive wiring material 60 may be deposited within opening 22. It follows that any of the materials discussed under prior embodiments could be used for the diffusion barrier 44, electrical contact enhancement layer 48, and the oxidation protection layer 46 of this damascene example.

[0031] One skilled in the art can appreciate that, although specific embodiments of this invention have been described above for purposes of illustration, various modifications may be made without departing from the spirit and scope of the invention. For example, FIG. 11 depicts an embodiment wherein the poly plug 28 is not recessed. As another example, shown in FIG. 12A, it is not necessary that the diffusion barrier 44 and the electrical contact enhancement layer 48 originate from the same material. In this example, the electrical contact enhancement layer 48 results from the silicidation of a selectively CVD'd titanium layer. The diffusion barrier 44, on the other hand, comes from nitridizing a tungsten layer that is over only the poly plug 28. Similarly, the diffusion barrier 44 in FIG. 12B comes from nitridizing a tungsten layer that conforms to the container 26 and overlies the TiSi_(x) electrical contact enhancement layer 48. Moreover, the current invention can be used in any situation wherein silicon is used to make an electrical contact. In addition, it should be noted that the invention becomes more beneficial as the silicon contact area decreases in size. Further, the end product and in-process versions of the product are also included within the scope of this invention. Finally, one skilled in the art can appreciate that the cross sections depicted the figures are not to scale. Rather, particular elements, such as the layers discussed above, are sized to clearly indicate embodiments of the current invention. Accordingly, the invention is not limited except as stated in the claims. 

What is claimed is:
 1. A method of establishing electrical communication between a first device and a second device in a semiconductor circuit, comprising: contacting said first device with a first end of an electrically conductive material; layering an initial barrier component over a second end of said electrically conductive material; nitridizing at least a portion of said initial barrier component; and contacting said second device with said portion of said initial barrier component.
 2. The method in claim 1, further comprising a step of siliciding at least a second portion said initial barrier component.
 3. The method in claim 2, wherein said step of contacting said first device further comprises contacting a transistor with doped silicon; and wherein said step of contacting said second device further comprises contacting a capacitor.
 4. The method in claim 3, wherein said step of contacting said second device further comprises contacting a capacitor with a doped polysilicon plug.
 5. A method of processing a semiconductor circuit on a substrate covered with an insulating layer, wherein said layer defines an opening over said substrate, and polysilicon contacts a surface of said substrate and a bottom of said opening; and wherein said method comprises: providing an initial barrier component on at least said polysilicon; and nitridizing said initial barrier component.
 6. The method in claim 5, further comprising siliciding said initial barrier component.
 7. The method in claim 6, further comprising a step of providing an oxidation protection layer within said opening.
 8. The method in claim 7, further comprising a step of recessing said polysilicon.
 9. The method in claim 8, wherein said step of providing an initial barrier component further comprises providing said initial barrier component only on said polysilicon.
 10. The method in claim 9, wherein said step of providing said initial barrier component comprises depositing said initial barrier component through selective chemical vapor deposition.
 11. The method in claim 9, wherein said step of providing said initial barrier component further comprises the steps of: depositing said initial barrier component on said polysilicon and within said opening; and etching said initial barrier component within said opening.
 12. A method of preparing a semiconductor device comprising a container defined by at least one insulation layer, comprising: forming a poly plug extending toward said container and having a surface under said container; depositing an initial barrier component at least between said poly plug and said container; and nitridizing a first portion of said initial barrier component, wherein said first portion is next to said container.
 13. The method in claim 12, further comprising a step of siliciding a second portion of said initial barrier component, wherein said second portion is between said poly plug and said first portion of said initial barrier component.
 14. The method in claim 13, further comprising a step of depositing an oxidation protection layer within said container and over said first portion.
 15. The method in claim 14, wherein said step of depositing an initial barrier component further comprises lining said container with said initial barrier component; and wherein said step of nitridizing a first portion of said initial barrier component further comprises nitridizing said initial barrier component lining said container.
 16. A method of forming an interface between a transistor and a capacitor, wherein said transistor includes a doped portion of a substrate, and an in-process poly plug is supported by said doped portion and extends upward along a length to a capacitor site, and wherein said method comprises: reducing said poly plug to generally half of said length; selectively chemically vapor depositing a barrier component onto said poly plug, wherein said barrier component has a bottom next to said poly plug and a top opposite from said bottom; and nitridizing said top of said barrier component.
 17. The method in claim 16, wherein said step of nitridizing further comprises nitridizing generally half of said barrier component.
 18. The method in claim 17, further comprising a step of siliciding said bottom of said barrier component.
 19. The method in claim 18, wherein said step of siliciding further comprises siliciding generally half of said barrier component.
 20. A method of interfacing a silicon contact with a semiconductor device, comprising: forming a barrier to diffusion from said silicon contact using a first material layered over said silicon contact; and forming a barrier to oxidation of said silicon contact using a selection of said first material and a second material.
 21. The method in claim 20, wherein said step of forming a barrier to oxidation further comprises providing a layer of ruthenium oxide.
 22. The method in claim 20, wherein said step of forming a barrier to diffusion further comprises layering over said silicon contact a selection of platinum, iridium, osmium, palladium, rhodium, ruthenium, and oxides thereof; and wherein said step of forming a barrier to oxidation further comprises forming a barrier to oxidation using said selection.
 23. The method in claim 20, wherein said step of forming a barrier to diffusion further comprises providing a metal nitride layer; and wherein said step of forming a barrier to oxidation further comprises providing a layer comprised of a selection of a metal or a metal oxide.
 24. The method in claim 23, wherein: said step of forming a barrier to diffusion further comprises providing a first layer selected from: a nitride of titanium, tungsten, rhenium, and platinum-group metals, an oxide of said platinum-group metals, an alloy of said platinum-group metals, and a boride of a transition metal; and said step of forming a barrier to oxidation further comprises providing a second layer over said first layer, wherein said second layer is selected from platinum-group metals and an oxide of platinum-group metals.
 25. A method of establishing electrical contact between a semiconductor substrate and a semiconductor device, comprising: covering said substrate with an insulating layer; etching a hole through said insulating layer to said substrate; partially plugging said hole with doped polycrystalline silicon; depositing at least one metal layer within said hole over said doped polycrystalline silicon; nitridizing said at least one metal layer; siliciding said at least one metal layer; and forming said semiconductor device over said at least one metal layer.
 26. The method in claim 25, wherein: said step of depositing at least one metal layer comprises depositing a titanium layer; said step of nitridizing said at least one metal layer comprises nitridizing said titanium layer; and said step of siliciding said at least one metal layer comprises siliciding said titanium layer.
 27. The method in claim 25, wherein: said step of siliciding said at least one metal layer comprises siliciding a titanium layer; said step of nitridizing said at least one metal layer comprises nitridizing a non-titanium layer; and said step of forming said semiconductor device further comprises forming said semiconductor device over said non-titanium layer.
 28. The method in claim 27, wherein said step of nitridizing a non-titanium layer comprises nitridizing a tungsten layer.
 29. A damascene process, comprising: forming a first insulation layer over a semiconductor substrate; forming a first hole in said first insulation layer; forming doped polysilicon in said first hole; and forming a silicon barrier over said doped polysilicon.
 30. The process in claim 29, wherein said step of forming doped polysilicon further comprises forming doped polysilicon having a low surface within said first hole.
 31. The process in claim 30, wherein said step of forming doped polysilicon having a low surface within said first hole further comprises: generally completely filling said first hole with said doped polysilicon; and etching a portion of said doped polysilicon.
 32. The process in claim 31, further comprising a step of forming an oxygen barrier over said silicon barrier.
 33. The process in claim 32, further comprising a step of forming an electrical contact enhancement layer under said silicon barrier.
 34. The process in claim 33, further comprising: forming a second insulation layer over said first insulation layer; and forming a second hole in said second insulation layer, wherein said second hole is over said first hole.
 35. The process in claim 34, wherein said step of forming an oxygen barrier further comprises forming an oxygen barrier extending into said second hole.
 36. A method of processing a semiconductor device, comprising: providing an silicon interconnect material contacting an electrically conductive first portion of said semiconductor device; and providing an initial barrier component contacting said interconnect material.
 37. The method in claim 36, wherein said step of providing an initial barrier component further comprises initially protecting said semiconductor device against silicon diffusion.
 38. The method in claim 36, wherein said step of providing an initial barrier component further comprises initially providing a component capable of protecting said semiconductor device against silicon diffusion after further processing.
 39. The method in claim 38, further comprising nitridizing said initial barrier component; and wherein said step of initially providing a component further comprises providing a component capable of protecting said semiconductor device against silicon diffusion after being nitridized.
 40. A method of preventing at least some diffusion from a conductive material in a semiconductor device, comprising: surrounding a side of said conductive material with an insulator; depositing a barrier material onto said conductive material; and nitridizing said barrier material.
 41. The method in claim 40, wherein said step of depositing a barrier material further comprises depositing said barrier material onto said conductive material and onto said insulator.
 42. The method in claim 41, further comprising a step of removing said barrier material from said insulator.
 43. A method of treating a silicon contact, comprising: depositing a barrier component onto said silicon contact; and nitridizing said barrier component.
 44. The method in claim 43, wherein said step of depositing a barrier component further comprises siliciding said barrier component.
 45. The method in claim 43, further comprising a step of discretely siliciding said barrier component.
 46. The method in claim 45, wherein said step of discretely siliciding said barrier component further comprises siliciding at least an un-nitridized portion of said barrier component.
 47. The method in claim 46, wherein said step of discretely siliciding said barrier component further comprises reacting said barrier component with silicon in said silicon contact.
 48. The method in claim 47, wherein said step of reacting said barrier component further comprises reacting said barrier component with a portion of said silicon contact containing oxygen.
 49. A memory cell, comprising: a transistor; a capacitor; a silicon plug extending from said transistor toward said capacitor and physically separate from said capacitor; and a diffusion barrier between said silicon plug and said capacitor.
 50. The memory cell in claim 49, wherein said diffusion barrier is made of a metal nitride.
 51. The memory cell in claim 50, wherein said diffusion barrier is made of titanium nitride.
 52. The memory cell in claim 51, further comprising an un-nitridized layer of titanium between said diffusion barrier and said silicon plug.
 53. The memory cell in claim 52, wherein said un-nitridized layer of titanium is a silicided layer of titanium.
 54. The memory cell in claim 53, wherein said silicided layer of titanium is generally as thick as said diffusion barrier.
 55. An interface between a poly plug and a storage node of a capacitor, comprising: an electrical contact enhancement layer over said poly plug; a silicon barrier over said electrical contact enhancement layer; and an oxidation protection layer over said silicon barrier and contacting said storage node.
 56. The interface in claim 55, wherein said electrical contact enhancement layer is a metal silicide layer; said silicon barrier is a metal nitride layer; and said oxidation protection layer is a layer selected from metals, metal oxides, and metal alloys including platinum.
 57. The interface in claim 56, wherein said electrical contact enhancement layer and said silicon barrier contain the same metal.
 58. The interface in claim 56, wherein said electrical contact enhancement layer is of a form TiSi_(x); and said silicon barrier is made of tungsten nitride.
 59. A part of a semiconductor circuit including insulation over an electrically conductive surface, wherein said insulation defines an opening and a hole from said opening to said surface, wherein said part comprises: a conductive material filling about half of said hole in said insulation, wherein said conductive material contacts said surface; and a diffusion barrier at least within said hole and over said conductive material.
 60. The part in claim 59, wherein said diffusion barrier lines said opening.
 61. The part in claim 60, further comprising an oxygen barrier conformal to said diffusion barrier.
 62. A portion of a semiconductor device having an electrically conductive first element, an electrically conductive second element contacting said first element, and an electrically conductive third element configured to electrically communicate with said first element through said second element, wherein said portion comprises: an oxidation barrier contacting said third element; and a silicon diffusion barrier contacting said oxidation barrier and said second element; wherein said oxidation barrier and said silicon diffusion barrier are configured to act as an electrical communication interface between said second element and said third element.
 63. The portion in claim 62, wherein said oxidation barrier and said silicon diffusion barrier define a continuous iridium layer.
 64. The portion in claim 62, wherein said oxidation barrier is made of ruthenium oxide; and said silicon diffusion barrier is also made of ruthenium oxide.
 65. The portion in claim 64, wherein said oxidation barrier and said silicon diffusion barrier define a continuous ruthenium oxide layer.
 66. An interconnect structure, comprising: a doped polysilicon material having a shape defined by an underlying support structure and an adjacent insulative material; an electrically conductive material over said doped polysilicon material and said insulative material; and a silicon barrier between said doped polysilicon material and said electrically conductive material.
 67. The structure in claim 66, wherein said silicon barrier contacts said doped polysilicon material and said electrically conductive material.
 68. The structure in claim 66, further comprising an oxidation protection layer contacting and interposed between said silicon barrier and said electrically conductive material.
 69. The structure in claim 68, further comprising an electrical contact enhancement layer contacting and interposed between said silicon barrier and said doped polysilicon material.
 70. An interface for a semiconductor device including a poly plug contacting a substrate and a capacitor plate over said poly plug, comprising: a diffusion barrier under said capacitor plate and over said poly plug, said diffusion barrier selected from a group consisting of: titanium nitride, tungsten nitride, rhenium, rhenium nitride, a platinum-group metal, a nitride of said platinum-group metal. an oxide of said platinum-group metal, an alloy of said platinum-group metal, a boride of a transition metal, and combinations of the above materials.
 71. The interface in claim 70, further comprising an oxidation barrier under said capacitor, over said diffusion barrier, and comprising a selection of a platinum-group metal and an oxide of said platinum-group metal.
 72. The interface in claim 71, further comprising an electrical contact enhancement layer under said diffusion barrier and over said poly plug, comprising a silicide material. 